Typhon is a free, open-source ebook reader that allows you to keep your reading progress synchronized across multiple devices. This means you can read a few pages on your phone, than grab your tablet continuing where you left off.
The lookup code takes its root on JadeReader. The dictionary lookup is called JRikai. It has instantaneous lookup, deconjugation, and longest match features which make looking up Japanese word definitions effortless. It also includes ENamdict for looking up Japanese names. Dictionaries are downloaded so that you can use all of the lookup functionality offline.